In the related art, replaceable cutting heads having a head body detachably attached to a tip of a tool body rotating around an axis by screwing are known. An outer periphery of the head body is provided with a plurality of chip discharge grooves that are arranged at intervals in a circumferential direction around an axis, cutting blades that extend along the chip discharge grooves, and a pair of latching faces that are formed by cutting the outer periphery of the head body in a planar shape and are arranged back to back with the axis interposed therebetween at a base end portion along the direction of the axis.
A work tool, such as a wrench, is made latchable (lockable) to the pair of latching faces, and a replaceable cutting head is rotated around the axis with respect to the tool body by this work tool and thereby, this replaceable cutting head is detached and attached.
For example, the following Patent Document 1 describes a replaceable working head rotating tool in which a fastening male thread and a fastening female thread respectively provided on axial centers on one and the other of a working head (replaceable cutting head) and a holder (tool body) are screwed to each other, and thereby, the working head is concentrically and detachably attached to a tip portion of the holder.
In this replaceable working head rotating tool, the working head and the holder are provided with abutting faces that are made to abut against each other in a fastened state where the fastening male thread and the fastening female thread are screwed to each other, and the fastening male thread and the fastening female thread are integrally rotationally driven via the holder in a tool rotational direction where the fastening male and female threads are fastened due to working load, and thereby, predetermined working is performed by the working head, and the abutment of the abutting faces prevents the fastening male thread and the fastening female thread from being further fastened with working load.
Additionally, Patent Document 1 describes that a pair of double-chamfered flat locking faces (latching faces_) are provided parallel to each other at symmetrical positions to an axial center at the head body of the replaceable cutting head, as tool locking portions (latching portions) to which a work tool for making the fastening male thread and the fastening female thread screwed to each other is locked.